Since blades of aircraft engines, such as turbine blades or compressor blades, are quite expensive to manufacture, such blades as a rule are repaired, if this is possible, in cases of damage or wear. Thus, a damaged or worn blade is not always replaced by a new one, but rather only if it is unavoidable.
So-called “patching” as a rule is used for repair of blades at present. To do so, via a cut, a part of a blade in which a damaged section is found is removed from the blade. Often this affects a section that contains the blade tip, because it is precisely in the area of the tip that damage or wear often appears. However, patching can also be done by means of standardized cuts.
Then, onto the severed segment of the blade, a new segment of identical form becomes the replacement. As a rule this occurs so that the new segment—if necessary still with some excess—is produced separately and fitted onto the remainder of the blade. Especially in cases in which the new segment has an excess, it is then processed, by which the target shape is generated.
This known procedure for blade repair, which typically is done manually, involves relatively high expense.
From other technical fields, thus not from the field of blade repairs, in other respects, so-called generative procedures are known. With these generative procedures, a component is assembled out of powder in layers, in that these individual layers are solidified under thermal action in combination with radiation energy. For reducing the thermal gradient in combination with crack formation, a (powder) layer can be provided with overall heating. With such supplementary heating or generative manufacturing procedures, two versions exist.
The one version involves use of an electrical heating plate with layered generative production. This is such that by means of a heating plate, the (metallic) component, including the initial material (powder) to be fabricated is heated, so that by means of this component (through thermal conductance) the area in which the next layer is to be applied is brought to a temperature necessary to melt the powder.
The second version is such that the operational space in which the generative manufacturing procedure is carried out is itself an oven. In other words, thus the component is generatively produced in an oven. The oven produces an even (high) temperature that is required to assemble the layer in question, and in the process necessarily heats the entire component to be assembled or shaped.
Specialists are in agreement that such generative manufacturing procedures can be used only to a limited degree and for quite limited purposes of use, but then have substantial disadvantages.
Thus, according to unanimous opinion in specialist circles, generative manufacturing procedures are considered to be totally unsuited when a danger exists that a large-area heating of the component or the component to be produced leads to substantial joint alterations and/or warping, and thus to considerable manufacturing imprecision.
A typical field of the type named previously, thus the type in which generative manufacturing is considered as totally unsuited for this field, is the field of blade repair for turbines or compressors of aircraft engines.
In other respects an additional difficulty in this specialty field is that blades that are distorted in uneven fashion as compared to each other, and in which the same rotors are used, can result in the rotor having considerable inhomogeneities in rotating. This would not only lead to a considerable increase in fuel consumption, but in addition, could possibly even be the cause of situations critical for safety.
With this as background, the task that is the basis for the invention is to provide a simple possibility of repairing blades or tips of blades for turbines or compressors of aircraft engines.